Process for alkylating phenols



Patented Feb. 14, 1939 UNITED STATES. PATENT 0mm PROCESS FOR ALKYLATINGPHENOLS Vladimir Ipatieil and Herman Pines, Chicago, 111., assignors toUniversal Oil Products Company, Chicago, 111., a corporation of DelawareNo Drawing. Application March 7, 1935, Serial No. 9,828

2 Claims.

ufacture of compounds of a cyclic character containing alkyl andhydroxyl groups.

More specifically the invention has reference 5 to a process formanufacturing derivatives of the class of compounds known generally asphenols which comprises either mono or polynuclear ring compoundscontaining hydroxyl groups.

The phenols constitute an important class of chemical compounds whichoccur in varying amounts in the products obtained when distillingvarious carbonaceous materials such as coal,

shale, lignite, peat, wood, etc.

Many of these individual compounds and the commercial mixtures obtainedfrom primary distillation products have value as germicides andinsecticides and as base products for the manufacture of moreoomplicated substances such as, for example, various resinouscondensation products produced by reacting phenols and aldehydes.

The following table gives a list of some of the mono nuclear phenols ofa mono, di and trihydric character:

'Ihe above table omits the citation ofcompounds in which 4, 5 or all 6of the original benzol hydrogen atoms are replaced by hydroxyl groups,although the 4 and 5 hydroxyl compounds may also be alkylated witholefin hydrocarbons according to the process of the present invention.

The general order of phenols includes also the three cresols, thecorresponding ethyl, propyl, .butyl and higher alkyl-substituted phenolsand the various isomerides which are possible when there is multiplesubstitution in the ring. Ex-

amplea of this more highly substitutedclals are This invention relatesparticularly to the manthe group comprising thymol and carvacrol whichare two of the twenty methyl isopropyl phenols.

The invention further comprises the manufac-' ture of derivatives ofpolynuclearphenols which are characterized by such compounds as alphanaphthol with a melting point of 94 C. and a boiling point of 297 C. andbeta naphthol with a melting point of 122 C. and aboiling point of Inone specific embodiment the present invention comprises the productionof derivatives of phenols by-treating them with unsaturated hydrocarbonscomprising olefins in the presence of phosphoric acid catalysts-thereactions being conducted with the phenols dissolved in nonpolarsolvents.

We have discovered that the production of derivatives of phenols bytreatment with unsaturated hydrocarbon compounds of an oleflniccharacter may be accomplished with greatly improved efliciency bydissolving the reacting constituents in polar solvents generally of ahydrocarbon character and by using phosphoric acid instead of suchpreviously used condensing agents as sulfuric acid and heavy metalchlorides including aluminum and zinc chlorides. when using suchreagents, particularly in the absence of suitably selected polarsolvents, the reactions of alkylation of phenols are attended by varioustypes of undesirable side reactions which decrease the yield of desiredproducts. For example. when using sulfuric acid of sufilcientconcentration to produce good yields of alkylated derivatives of phenolsby reacting olefins therewith, there is always an undesirable amount ofsulphonation and tar formation. With aluminum chloride and similarcompounds there is also a considerable loss on account of the formationof addition compounds of an intermediate character which gradvalue.

ually resinify to produce heavy residues of no- In contrast to thediificulties experienced previously the use of solvents and phosphoricacid (and other suitable acids of phosphorus) according to the processof the present invention minimizes the side reactions and produces highyields of compounds of the desired character, to-wit, phenols with ringhydrogen atoms substituted by As will be developed in a later example,the use of solutions of phenols in proper solvents rather than phenolsalone results in maximum yields of the desired substituted compounds andminimum yields of isomeric mixed alkyl residues.

others, in contrast solvents.

to the yields produced without Thev reactions involved in the presentinvention are essentially those between certain types of so-calledunsaturated hydrocarbons and phearc-nose to use pressures aboveatmospheric whenever necessary or advantageous. This type of operationis essentially a .batch procedure, the introduction '01 the olefin vaporbeing continued until the desired degree of alkylation is effected,- atwhich time the stream of vapor is stopped and the acid catalyst allowedto settle, the solution ofreaction products being run off into suitablestoroptio'nal use of superatmospheric pressure will depend principallyupon the volatility of the'solvent used and the temperature found mostsultable for interacting a given phenol and a given 75 olefinor-different mixtures of both groups, and

-. other or it maybe employed to produce mixtures of alkylated productsby using either phenolic mixtures or oleflnic mixtures or both. Forexampie, amixture of alkyia'ted derivatives may be produced byreactingthe tax-acids it is comprised within the scope it the inventioness leading to the production of j derivatives of age while the partlyspent catalyst is subjected phenols are generally of a'hydrocarboncharacter to any suitable necessary purifying or regener-- and includestraight chain paraflln hydrocarating steps before being further used.The steps bons of moderate boiling point, benzol, cyclo; of removing thesolvent, and separating the dehexane, etc. ese compounds aresubstantiaisired reaction products from the compounds rely unreactive bt at the same timecause dilusuiting from unavoidable side. reactions mayintion. of the reacting constituents and moderate -volve fractionaldistillation, fractional crystal-f the action of the catalyst so thatside reactions lization or any other procedure which is, found areminimizedand maximum yields ofdesired to :be essential.

I products are obtained. In contrast to this class An effective methodof contacting which may of solvents maybe mentioned water, acetic acid,be applied to continuous operation consists in alcohols, etc. which areof. a decidedly polar charforcibly injecting olefin vapors, acidcatalyst and acter and usually have an adverse effect even solutions ofphenols into mixing devices posiwhen the reactants are 'suflicientlysoluble theretioned inflide'ithe p 1 filled columns, h mulin 'tomaketheir use possible. sion' produced being allowed to trickle down- 1 Inthe matter of catalysts th'e commoner acid wardly ov r the fi n at ria tpl t the of phosphorus such a th w ll k w rth initiated reactions,- allreaction products being phosphoric acid and pyro phosphoric acid' arewithdrawn from the bottom of the tower and generally preferable onaccount of their ready p ted as b orev availability and moderate cost.It is also com- T 'm in' course of the reactions which occur prisedwithin the scope of the invention to emw s ns O Phenols re treated withole- -p1oy any of the acids of phosphorus-alone or in fins in thepresence of phosphoric acids 13111118- admixture insofar as beneficialand economical "trated by he followin equations: 1 results areobtainablethereby. The phosphoric mp0 7 acids in which phosphorus has 'a valenceof 5 are generally preferable over the phosphorus K acids. Thesealternative reagents are not pro- 9 posed as exactequivalents' sincetoanyone suf-. PmPYlm MPNPYIPWI flciently conversant with the chemicalartit is' on HzPO; cm,

i obvious that each will exert its own particular- 0 1 (hm-01! 40 eflectin any given case. In the .table below-a R v i tabulation of the-names,formulas and com- 1 Y moner properties of the acids of phosphorus is I MEthylene Mcthvl-cthrlphcml appended. Reactions ofthe above. charactermaybe made Acids ofphosphorus $1.13. o. Dec.0

5 o t it'rid $3; P .0 ht fis $033M mac. r,oisn,o aao J isovp phoephoncBrno. rroasmo 55.0 10 r lxpgig ric 113 1;:8 l fiiai hmlc mo. mam z 'tzusac mart-{martian 5s a a In producing alkyl derivatives.of phenols by tooccur inpredominating amounts, frequently employing olefln's-as theaikylating agents ac- 95%- of the phenol being converted to mono cordingto the process of the present invention derivatives without causing theproduction of the exact mode of procedure will vary with the phenolicethers. Limited amounts of diand 60 nature of the reacting constituents.A very slim tri-substituted products may also be produced.

pie procedure in the case of phenols. which are It 15 8 Particularfeature 0! the P e nt invensuiliciently soluble in such polarhydrocarbon tion that when employing substantially neutral solvents suchas cyclohexane, and oieflns which and unreactive hydrocarbon solventsthere is a are gaseous or readily vaporized, consists in greatlydiminished tendency for the formation the olefin vapor into a suspensionof of mixed ethers of both an aryl and an alkyl phosphoric acid ,in thesolution of phenol, inticharacter in contrast to the products of thesame mate contacting of the reacting compounds with reactions when nosolvents are employed. acid catalyst being assured byeither vigorous Theprocess may be employed to effect the mechanical agitation or theforcible injection of reaction between chemical individuals compristhevapors in the form of fine bubbles. The ing phenols on the one hand andoleflns on the from various crude tars by caustic alkali (and lateracidification) with olefin-containing gas mixtures such, for example, asthose encountered in oil cracking processes either aimed primarily atthe production of gasoline or of fuel gas. Mixtures thus produced mayfind application as germicidal, insecticidal or disinfecting material ormay in some cases be employed as inhibitors or anti-oxidants forpreventing the formation of gummy and resinous polymers from the olefinscontained in such materials as cracked gasoline or commercial fuelgases. It is a matter of frequent observation though not always ageneral rule that the presence of alkyl substituting groups in phenolscorresponds to increased inhibiting value. For example, phenol itselfhas a relatively low value for preventing the deterioration of crackedgasoline upon storage whereas a mixture of cresols commonly known astri-cresol has greatly increased value in this respect. The substitutionof alkyl residues of higher molecular weight than the methyl residue,for example, the butyl residue, has been observed to still furtherincrease the value as inhibitors of the base phenolic substances.

The following examples are given to show the character of the resultsobtainable when interacting olefins with phenols according to thepresent process although the data are not introduced for the purpose ofnarrowing the scope of the inof the reaction products remainedinsoluble, indicating that they were ethers.

Run II Fifty parts by weight of metacresol were heated with 25 parts byweight of 100% phosphoric acid at atmospheric pressure with refluxing.The temperature was held at 120 C. and a stream of pure propylene waspassed in for 5 hours. .The acid and oil layers were again separated andin this case the treatment. of the latter with 20% caustic sodaindicated that only 20% wasinsoluble.

Run III In this run the conditions employed in Example I in regard toquantities of materials, temperature and pressure were repeated but thecresol was dissolved in about 2 volumes of cyclohexane. As a result ofthis test it was found after separation of the acid layer and removal ofthe solvent by distillation that only 5% of insoluble ethers had beenproduced.

Run IV In this run the conditions and quantities of Run I were used withthe exception of the fact that 90% orthophosphoric acid was used insteadof 100% acid. In this case it was found that 25% of alkali-insolubleethers had'been produced.

The following table summarizes the overall vention. results of thesefour experiments.

Run I Run II Run III Run IV Percent phosphoric acid p 100 100 100 90Temperature, O 120 120 120 120 Pressure Super-atmospheric AtmosphericSuperatmosplieric Superetmospheric Solvent None None Cyclohexane NonePercent alkali insoluble prodnct 60 20 6 26 The following exampleillustrates the improved results normally obtainable in alkylating aparticular phenol with a particular olefin using phosphoric acid andsolvents according to the present process.

A series of four runs were made in alkylating metacresol with propylene.In three of the runs 100% liquid orthophosphoric acid was used and inone run 90% acid. The temperature employed in all runs was 120 C. andboth atmospheric and superatmospheric conditions were employed. Theatmospheric pressure runs were run under reflux conditions in glassapparatus and the superatmospheric runs were made in rotating bomsequipped with-glass liners to eliminate corrosion.

Run I Thirty parts by weight of 100% phosphoric acid was heated with 60parts by weight of metacresol and 32 parts by weight of propylene for 12hours at a temperature of 120 C. The maximum pressure developed was ofthe order of 30 atmospheres. After cooling, the residual pressure wasreleased and the acid and oil layers separated.

- The oil layer was treated with a 20% solution of sodium hydroxide andit was found that 60% The above data indicates that the best overallresults were obtained in Run III in respect to the production .ofminimum quantities of alkali insoluble ethers, which shows thesuperiority of the present process over other methods of operation.

The foregoing specification has disclosed the character of the inventionand the experimental data shown have indicated its possibilities but theinvention is not limited to the specific details of the description northe numerical data.

We claim as our'invention:

1. A process for alkylating phenols which comprises subjecting a phenolto the action of an olefin hydrocarbon in the'presence of an acid ofphosphorus and a non-polar solvent, said solvent being in suflicientamount to produce not substantially in excess of 5% alkali insolubleether in the reaction product of the process.

2. A process for alkylating phenols which comprises subjecting a phenolto the action of an olefin hydrocarbon in the presence of a phosphoricacid and a non-polar solvent, said solvent being in sufficient amount toproduce not substantially in excess of 5% alkali insoluble ethers in thereaction product of the process.

VLADIMIR. IPA'I'IEFF. HERMAN PINES.

